Large numbers of cargo containers, ships, and planes are received at shipping ports, borders, and transportation centers each day and each one presents a potential opportunity for unauthorized delivery of a nuclear device, such as a radiological weapon (e.g. a small dirty bomb). In addition, smuggling of devices out of a location is also a concern in order to keep terrorists and other unauthorized entities from obtaining such devices.
While many types of radiation detectors have been developed, one of the more promising types appears to be a Silicon-On-Insulator (SOI) Static Random Access Memory (SRAM) structure used in conjunction with one or more neutron conversion layers, such as those doped with boron (e.g. boron-10). For example, U.S. Pat. Nos. 6,867,444 and 7,271,389, assigned to the United States Navy, set forth two such devices and are hereby incorporated by reference herein in their entireties. However, these devices require substrates with a heavily doped buried layer, which is complicated to prepare and process. Post-circuit processing is also made difficult due to the conversion layer being buried in the substrate.
Therefore, a neutron detection structure that is easily manufacturable and utilizes commercially available SOI SRAMs would be desirable. The structure should allow for unattended detection of neutrons emitted from small nuclear devices, for example.